what voltage when thr motor is running 89 evinrude 40hp

[drakewoodie]

I have an evinrude 40hp that the battery died on me the other day while on the lake. I hooked up a digital voltmeter to the battery and with the motor running its at 12.8V is this the correct voltage. I'm kinda thinking I just bought to small of a battery and killed it by running the livewell pump too long. What size of battery should I have?

 

[F_R]

Re: what voltage when thr motor is running 89 evinrude 40hp

How long had it been running when you recorded the voltage? What was the voltage when you first started it? The voltage should slowly increase as the motor runs, indicating the alternator is charging the battery.